Islamabad, Jan 30

At least 20 people were reportedly killed and 55 injured in an explosion inside a central imambargah -- mosque affiliated with Shia Muslims -- in Pakistan's Sindh province Friday.

Over 55 people were injured in the blast that was heard several kilometres away. Children are also reportedly among the dead and injured, The News International reported citing Shaukat Memon, medical superintendent of Civil Hospital in Shikarpur.

The imambargah is located in Lakhi Dar area of Shikarpur district and the explosion occurred just after Friday prayers.

A number of victims were trapped under the debris after the roof of the imambargah collapsed due to the force of the blast.

The condition of the wounded is said to be critical.

While describing the incident a failure of the government, Majlis Wahdatul Muslimeen (MWM) announced a three-day mourning.

Sindh Information Minister Sharjeel Inam Memon said that emergency has been imposed at all hospitals in Shikarpur and surrounding talukas and cities.

Prime Minister Nawaz Sharif, President Mamnoon Hussain, Pakistan Tehreek-i-Insaf chairman Imran Khan and Muttahida Qaumi Movement chief Altaf Hussain issued messages condemning the incident.

A bomb disposal squad has been dispatched to the area from Sukkur and rescue teams have reached the imambargah where the explosion took place.

Speculation prevails that a suicide bomber may have carried out the explosion.

It is the second major attack on an imambargah in the country since the beginning of 2015, the first being an attack on Rawalpindi's imambargah Aun Mohammad Rizvi in the garrison city's Chatian Hatian area.